The oxide which acts as a reducing, oxidising, bleaching agent and a Lewis base is

Options

A. `SO_(2)`
B. `SO_(3)`
C. `CO_(2)`
D. `NO`

Answer

To solve the question regarding which oxide acts as a reducing agent, oxidizing agent, bleaching agent, and Lewis base, we will analyze the given options: SO2, SO3, CO2, and NO.

### Step-by-Step Solution:

1. **Identify the Oxidation States**:
- For **SO2**:
- Let the oxidation state of S be \( x \).
- The equation is \( x + 2(-2) = 0 \) (since there are two O atoms, each with an oxidation state of -2).
- Solving gives \( x - 4 = 0 \) → \( x = +4 \).
- For **SO3**:
- The equation is \( x + 3(-2) = 0 \).
- Solving gives \( x - 6 = 0 \) → \( x = +6 \).
- For **CO2**:
- The equation is \( x + 2(-2) = 0 \).
- Solving gives \( x - 4 = 0 \) → \( x = +4 \).
- For **NO**:
- The equation is \( x + (-2) = 0 \).
- Solving gives \( x + 2 = 0 \) → \( x = +2 \).

2. **Analyze the Reducing and Oxidizing Properties**:
- **SO2** can act as both a reducing agent (it can be oxidized from +4 to +6) and an oxidizing agent (it can reduce other substances).
- **SO3** is a strong oxidizing agent but does not act as a reducing agent.
- **CO2** is primarily an oxidizing agent and does not have reducing properties.
- **NO** can act as a reducing agent but does not serve as a bleaching agent.

3. **Bleaching Agent**:
- **SO2** is known to have bleaching properties, especially in the context of organic compounds.
- **SO3** and **CO2** do not have bleaching properties.
- **NO** does not act as a bleaching agent.

4. **Lewis Base**:
- **SO2** can donate a pair of electrons, thus acting as a Lewis base.
- **SO3** and **CO2** do not exhibit Lewis base behavior.
- **NO** does not act as a Lewis base.

5. **Conclusion**:
- Among the given options, **SO2** is the only oxide that acts as a reducing agent, oxidizing agent, bleaching agent, and a Lewis base.

### Final Answer:
The oxide which acts as a reducing agent, oxidizing agent, bleaching agent, and a Lewis base is **SO2**.